There is a wall in the Ohio State football coaching staff’s meeting room filled with magnets representing individual players, the depth chart that might as well be considered the contingency plan in terms of putting a team on the field.

When things go awry with personnel, from injuries and academic ineligibilities to what coach Urban Meyer is dealing with now — legal problems for running back Carlos Hyde and cornerback Bradley Roby — just a week before preseason camp begins, he turns to the wall.

“I have magnets that I will stare at, move them around,” Meyer said. “It’s like a checkerboard: I can see what we have. As long as I can see some depth at those positions — for example, at running back — I’m good.”

Hyde, who’s being investigated by Columbus police on a complaint of physical assault brought by a woman in a Downtown bar, has been suspended, and his status is in limbo. But Meyer still has Rod Smith, Bri’onte Dunn, Warren Ball and freshman Ezekiel Elliott on the wall.

“What I’m really concerned about is our offensive line,” Meyer said. “Some speed bump hits one of those starters, I don’t have confidence in the magnets below them yet. The same with our linebacker spots. I really like our first group of magnets. The second group? I don’t know.”

And at cornerback, if Roby — arrested a week ago in Bloomington, Ind., and charged with misdemeanor assault after allegedly getting into a confrontation with bouncers at a bar — ultimately must sit a game or two for his transgression, Adam Griffin, Armani Reeves, Eli Apple or some other fast riser in camp might see his magnet move.

But a football team is rarely like a race car, which, when a tire goes bad, the pit crew just bolts on another that is of comparable quality. Those individual magnets on Meyer’s wall represent different players in terms of height, weight, speed, experience and drive. Sometimes the loss of a key magnet or two can turn into a domino effect that takes a great team to good or mediocre.

For example, Southern California went into the 2012 season No. 1 in the Associated Press poll. Several developments later, including the loss of a key lineman on each side of the ball and finally senior quarterback Matt Barkley to a shoulder injury, the Trojans finished the season 7-6, including a loss to Georgia Tech in the Sun Bowl.

“The complexity of this machine that we’re expected to coach, (made up of) 18- to 22-year-old males, in an extremely competitive environment that’s overhyped — it’s a slippery slope,” Meyer said. “If you really thought about it, there’s hundreds of examples throughout the last decade. Maybe not at the No. 1 level, but I have been around teams where you thought you were pretty darn good and all of a sudden …”

In Meyer’s second year as a graduate assistant at Ohio State in 1987, the Buckeyes were considered one of the top three teams before the season. Then Cris Carter, arguably the country’s best receiver, was declared ineligible by the NCAA after admitting to taking money from agents. The Buckeyes’ other starting receiver, Nate Harris, became academically ineligible.

The contingency: Everett Ross was moved up to starting receiver, and coach Earle Bruce soon moved running back Vince Workman to receiver. Ten games into the season, the Buckeyes, also hampered by injuries, were 5-4-1, “and we were fired,” Meyer said. The rally to beat Michigan the next week was the exit curtsy for the coaching staff.

“So it’s complex,” Meyer said.

Michigan coach Brady Hokes knows that firsthand. He agreed to play a season opener last year against defending national champion Alabama in Arlington, Texas. A month before the game, he knew he had to suspend starting tailback Fitzgerald Toussaint, who had been charged with DUI. The Wolverines were blasted in the game, and along the way Denard Robinson, their primary offensive threat, suffered an elbow injury that slowed him the rest of the season. Michigan slumped to 8-5.

“When you talk about a contingency plan, I don’t know that you are ever prepared for some things that may happen,” Hoke said. “Who knew Fitz was going to have an issue? I didn’t know that.”

Going into Hoke’s third year at Michigan, the depth chart indicates that the Wolverines are better equipped to roll with some punches.

“We’re in a better place now because of depth; that’s a real positive,” Hoke said. “But you always have to be ready for the different changes you may need to make.”

Penn State coach Bill O’Brien said he spends time each day with his staff talking through such scenarios, ranging from replacing a player who might have to leave a game with a broken shoelace to the potholes that might have to be filled because of injuries, ineligibilities or transfers.

“Then for the future, we think about as it relates to projecting how many kids we can sign at the different positions,” O’Brien said. “Do we need more running backs, things like that. And then you have to expect the unexpected. Are there going to be guys that leave early and go to the pros? What happens then? We definitely think about it.”

On top of that, last year and this year O’Brien’s upperclassmen were eligible to transfer without a one-year penalty because of sanctions — including four years of 65 total scholarships, down from 85 — that the NCAA levied the football program after the Jerry Sandusky scandal.

“We don’t see it as daunting; we just see it as a challenge that nobody has ever had to go through in coaching,” O’Brien said.

It’s called rolling with the punches, but sometimes the countermoves don’t work out.

“It happens every day in sports: When a team fails, it’s not just because it’s a bad coach,” Meyer said. “It’s easy to say it’s the coach’s fault, but there’s something that happened. Was Coach Bruce a bad coach (in 1987)? He’s a great coach. He lost two great players.